RESUMEN
LcrF (VirF), a transcription factor in the multiple adaptational response (MAR) family, regulates expression of the Yersinia type III secretion system (T3SS). Yersinia pseudotuberculosis lcrF-null mutants showed attenuated virulence in tissue culture and animal models of infection. Targeting of LcrF offers a novel, antivirulence strategy for preventing Yersinia infection. A small molecule library was screened for inhibition of LcrF-DNA binding in an in vitro assay. All of the compounds lacked intrinsic antibacterial activity and did not demonstrate toxicity against mammalian cells. A subset of these compounds inhibited T3SS-dependent cytotoxicity of Y. pseudotuberculosis toward macrophages in vitro. In a murine model of Y. pseudotuberculosis pneumonia, two compounds significantly reduced the bacterial burden in the lungs and afforded a dramatic survival advantage. The MAR family of transcription factors is well conserved, with members playing central roles in pathogenesis across bacterial genera; thus, the inhibitors could have broad applicability.
Asunto(s)
Proteínas Bacterianas/antagonistas & inhibidores , Bencimidazoles/farmacología , Neumonía Bacteriana/patología , Factores de Transcripción/antagonistas & inhibidores , Infecciones por Yersinia pseudotuberculosis/patología , Yersinia pseudotuberculosis/efectos de los fármacos , Yersinia pseudotuberculosis/patogenicidad , Animales , Antibacterianos/administración & dosificación , Antibacterianos/síntesis química , Antibacterianos/química , Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Bencimidazoles/administración & dosificación , Bencimidazoles/síntesis química , Bencimidazoles/química , Línea Celular , Modelos Animales de Enfermedad , Femenino , Humanos , Pulmón/microbiología , Macrófagos/microbiología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/mortalidad , Factores de Transcripción/metabolismo , Resultado del Tratamiento , Virulencia , Yersinia pseudotuberculosis/metabolismo , Infecciones por Yersinia pseudotuberculosis/tratamiento farmacológico , Infecciones por Yersinia pseudotuberculosis/microbiología , Infecciones por Yersinia pseudotuberculosis/mortalidadRESUMEN
ExsA is a multiple adaptational response (MAR) transcription factor, regulating the expression of a virulence determinant, the type III secretion system (T3SS) in Pseudomonas aeruginosa. Non-cytotoxic, non-antibacterial N-hydroxybenzimidazoles were identified as effective inhibitors of ExsA-DNA binding, and their potential utility as anti-virulence agents for P. aeruginosa was demonstrated in a whole cell assay. Select N-hydroxybenzimidazole inhibitors were stable in an in vitro human liver microsomal assay.
Asunto(s)
Bencimidazoles/antagonistas & inhibidores , Pseudomonas aeruginosa/efectos de los fármacos , Factores de Transcripción/antagonistas & inhibidores , Virulencia/efectos de los fármacos , Humanos , Microsomas Hepáticos/efectos de los fármacos , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidadRESUMEN
LcrF, a multiple adaptational response (MAR) transcription factor, regulates virulence in Yersinia pestis and Yersinia pseudotuberculosis. In a search for small molecule inhibitors of LcrF, an acrylic amide series of N-hydroxybenzimidazoles was synthesized and the SAR (structure-activity relationship) was examined. Selected test compounds demonstrated inhibitory activity in a primary cell-free LcrF-DNA binding assay as well as in a secondary whole cell assay (type III secretion system dependent Y. pseudotuberculosis cytotoxicity assay). The inhibitors exhibited no measurable antibacterial activity in vitro, confirming that they do not target bacterial growth. These results demonstrate that N-hydroxybenzimidazole inhibitors, exemplified by 14, 22, and 36, are effective antivirulence agents and have the potential to prevent infections caused by Yersinia spp.
Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Bencimidazoles/química , Bencimidazoles/farmacología , Transactivadores/antagonistas & inhibidores , Yersinia pestis/efectos de los fármacos , Yersinia pseudotuberculosis/efectos de los fármacos , Animales , Antibacterianos/síntesis química , Antibacterianos/uso terapéutico , Proteínas Bacterianas/metabolismo , Bencimidazoles/síntesis química , Bencimidazoles/uso terapéutico , Línea Celular , Sistema Libre de Células/metabolismo , ADN/metabolismo , Descubrimiento de Drogas , Concentración 50 Inhibidora , Ratones , Peste/tratamiento farmacológico , Relación Estructura-Actividad , Transactivadores/metabolismo , Virulencia/efectos de los fármacos , Yersinia pestis/patogenicidad , Yersinia pseudotuberculosis/patogenicidadRESUMEN
Structure-based drug design was utilized to identify potent small-molecule inhibitors of proteins within the AraC family of bacterial transcription factors, which control virulence in medically important microbes. These agents represent a novel approach to fight infectious disease and may be less likely to promote resistance development. These compounds lack intrinsic antibacterial activity in vitro and were able to limit a bacterial infection in a mouse model of urinary tract infection.
Asunto(s)
Antibacterianos/química , Antibacterianos/uso terapéutico , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/metabolismo , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/metabolismo , Animales , Antibacterianos/síntesis química , ADN/genética , Modelos Animales de Enfermedad , Enterobacteriaceae/efectos de los fármacos , Concentración 50 Inhibidora , Ratones , Estructura Molecular , Unión Proteica , Pseudomonas aeruginosa/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Relación Estructura-Actividad , Infecciones Urinarias/tratamiento farmacológico , Infecciones Urinarias/microbiologíaRESUMEN
Treatment of infections is compromised worldwide by the emergence of bacteria that are resistant to multiple antibiotics. Although classically attributed to chromosomal mutations, resistance is most commonly associated with extrachromosomal elements acquired from other bacteria in the environment. These include different types of mobile DNA segments, such as plasmids, transposons, and integrons. However, intrinsic mechanisms not commonly specified by mobile elements-such as efflux pumps that expel multiple kinds of antibiotics-are now recognized as major contributors to multidrug resistance in bacteria. Once established, multidrug-resistant organisms persist and spread worldwide, causing clinical failures in the treatment of infections and public health crises.
Asunto(s)
Antibacterianos/farmacología , Bacterias/genética , Farmacorresistencia Bacteriana Múltiple/genética , Bacterias/efectos de los fármacos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Cromosomas Bacterianos/genética , Conjugación Genética , Genes Bacterianos , Genes Reguladores , Transducción Genética , Transformación GenéticaRESUMEN
MarA, SoxS and Rob are transcription factors belonging to the AraC family. While these proteins have been associated historically with control of multiple antibiotic resistance, and tolerance to oxidative stress agents and organic solvents, only a paucity of experimental data support a role in regulating virulence. Clinical Escherichia coli isolates, and isogenic strains lacking marA, soxS and rob, were studied in a murine model of ascending pyelonephritis, which is a clinically relevant model of urinary tract infection. Organisms lacking all three transcription factors (triple knockouts) were significantly less virulent than parental strains, and complementation studies demonstrated that the addition of marA, soxS and rob individually restored wild-type virulence in the triple-knockout strain. Deletion of soxS or rob alone was more detrimental than the removal of marA. Thus, all three proteins contribute to virulence in vivo.
Asunto(s)
Proteínas de Unión al ADN/fisiología , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/fisiología , Escherichia coli/patogenicidad , Pielonefritis/microbiología , Transactivadores/fisiología , Factores de Virulencia/fisiología , Animales , Proteínas de Unión al ADN/genética , Modelos Animales de Enfermedad , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Eliminación de Gen , Prueba de Complementación Genética , Ratones , Transactivadores/genética , Infecciones Urinarias/microbiología , Virulencia/genética , Factores de Virulencia/genéticaRESUMEN
The development of new antibiotics is crucial to controlling current and future infectious diseases caused by antibiotic-resistant bacteria. Increased development costs, the difficulty in identifying new drug classes, unanticipated drug toxicities, the ease by which bacteria develop resistance to new antibiotics and the failure of many agents to address antibiotic resistance specifically, however, have all led to an overall decline in the number of antibiotics that are being introduced into clinical practice. Although there are few, if any, advances likely in the immediate future, there are agents in both clinical and preclinical development that can address some of the concerns of the infectious disease community. Many of these antibiotics will be tailored to specific infections caused by a relatively modest number of susceptible and resistant organisms.
Asunto(s)
Antibacterianos/uso terapéutico , Industria Farmacéutica/tendencias , Drogas en Investigación/uso terapéutico , Animales , Antibacterianos/síntesis química , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiología , Ensayos Clínicos como Asunto/estadística & datos numéricos , Ensayos Clínicos como Asunto/tendencias , Farmacorresistencia Bacteriana/fisiología , Drogas en Investigación/síntesis química , HumanosRESUMEN
The recent 44th annual Interscience Conference on Antimicrobial Agents and Chemotherapy provided a snapshot of the antibiotics most advanced in clinical development. New antibiotic discovery programs and novel efforts in the field of non-antibiotic treatment modalities were also presented. Some of the most pressing issues in antibiotic resistance were discussed at this meeting.